For the purpose of enrichment and/or purification and/or dressing or refining, it is known to cause substances having different properties which are harmonized with one another and, as a rule, a different state to penetrate one another and in so doing to act, on one another. In order to ensure controlled reproducible penetration and effect conditions, stratification methods and procedures possibly along with the use of separating and enrichment and/or purification elements are known.
For the supplying of cultures with water and oxygen, besides the customary surface sprinkling or aeration, supply from an underlying store along with the use of double-bottom containers is known. The construction of such containers with an upper bottom as separating element between the soil culture that is to be supplied and the storage space and an actual container lower bottom tightly sealing the same off downwardly has in the past been achieved in any of the following ways:
(a) The upper bottom is, like the lower bottom, an integral constituent prt of the container walling. PA0 (b) The upper bottom is an integral constituent and the walling of an internal container and the lower bottom is an integral constituent part of an external container. PA0 (c) The upper bottom is supported on supporting noses which are an integral constituent part of the container walling. PA0 (d) The upper bottom is supported on supporting uprights or supporting pillars, which are either an integral constituent part of the upper bottom or of the lower bottom. PA0 (e) The upper bottom is supported on supporting uprights or supporting pillars which are detachable structural elements.
The upper bottoms in accordance with (a) and (b) are given their bering capacity chiefly through their connection to the container walling and possibly additionally through an arched shaping (bottle bottom). The upper bottoms in accordance with (c) to (e) are as a rule flat and, depending on the frequency and spacing of the supporting elements, more or less stiff or flexible; the force transmission to the container wall or the lower bottom takes place primarily punctiformly or linearly. The upper bottoms in accordance with (a) to (e) are in themselves single-walled in design and possibly ribbed and they can be perforated in a sieve-like -or lattice-like manner. They are, as a rule, produced from metal or plastics material.
Transportation of the medium present in the store onto and into the soil culture takes place in the case of gases in a natural way by convection and pressure or partial pressure gradients. Where the gas is disposed an an intervening layer above a stored liquid, transportation of evaporated liquid takes place at the same time as transport of the gas. This liquid transportation can additionally be considerably enhanced by absorbent (hygroscopic) wick cords, ribbons or webs, which lead from the liquid store into or onto the soil culture.